A significant (i.e. 2%) fuel economy and/or emissions improvement can be obtained in multi-cylinder internal combustion (IC) engines if the fuel mixture is accurately balanced in all cylinders. This requires close control of combustion chamber volume, a difficult proposition using standard manufacturing techniques. This invention describes means for doing so using optical sensing and feedback to machining operations. Applications also exist to the more controlled manufacture of gears and other contoured surfaces.
Techniques according to the invention to produce better combustion chamber matching are:
(A) Mill or otherwise machine bank face of cylinder head to optimally suit head casting. PA0 (B) Do `A` and/or also trim each chamber to size, for example, by removing or adding additional material in certain areas, or controlling the machining of valve seat height, according to measured volume data. PA0 (C) Finish machine chambers in cylinder head to match displaced volume of pistons in finished engine.
All of the above depend on rapid, on-line, accurate measurement of combustion chamber shape and volume, (and in `C`, piston domes and height relative to bank face of block i.e. "deck height"). This can only be done optically in any practical manner. Previous means to determine volume via displaced water, sound waves and the like are totally unsuited to modern automatic production.
A typical optical sensor of the triangulation type capable of doing the required dimensional measurement is shown in copending application of Pryor et al, Ser. No. 34,278, now U.S. Pat. No. 4,373,804, issued Feb. 17, 1983, filed Apr. 30, 1979, the disclosure of which is herein incorporated by reference. Alternately, a multi-contact optical sensor can be used, derived from those shown in another copending application of Pryor, Ser. No. 134,465 now U.S. Pat. No. 4,403,860, issued on Sept. 13, 1983, filed Mar. 27, 1981, the disclosure of which is herein incorporated by reference.
While most applications of the invention envision material removal to attain proper dimensions, it is possible as well to add material. One example would be to use a valve whose head displaces more volume, if the volume in that chamber was excessive.
An alternative technique disclosed is to measure the chamber volumes and input this data to fuel system controls to vary the mixture into each cylinder according to its individual volume. This adjustment of the fuel system according to volume is most practical where individual fuel injection is utilized for each cylinder.
A related idea relative to gears is to measure gear teeth contours and cut them to print size, or to provide a Match to characteristics of another gear already measured, to prove quieter operation and other advantages. Other examples of such controlled machining can be controlled forming of turbine blades etc.
Another aspect of the invention is in controlled deburring of parts, wherein optical sensing according to the invention is used to determine presence and size of burrs and actuate a laser or other machining means to remove burrs present exceeding a certain value and/or at a certain position.